Major storm produces thundersnow over Sioux Falls, South Dakota

Major storm affecting much of the United States since Wednesday, April 10, 2019, produced a relatively rare weather phenomenon over central South Dakota known as thundersnow.

"It's essentially a thunderstorm, but it's cold enough for snow," said Mike Connely, a weather service meteorologist in Aberdeen, South Dakota 

Snow produced by the storm was falling at a rate of up to 5 cm (2 inches) per hour in northeastern South Dakota and southwestern Minnesota on Wednesday.

South Dakota Governor Kristi Noem closed state government offices in 52 counties. Numerous schools around the state closed, along with several Black Hills National Forest offices in western South Dakota and eastern Wyoming.

NWS posted an ice storm warning into Friday morning, April 12 for a portion of southern Minnesota, saying up to three-fourths of an inch (19 mm) of ice could accumulate on power lines, leading to power outages.

Read more: Major storm system producing widespread hazardous weather across much of the Central U.S.